perf(get): reuse reader paths and lock namespaces (#6015)

Co-authored-by: heihutu <heihutu@gmail.com>

crates/lock/src/distributed_lock.rs

@@ -479,7 +479,7 @@ pub struct DistributedLock {
     /// Lock clients for this namespace
     clients: Vec<Arc<dyn LockClient>>,
     /// Namespace identifier
-    namespace: String,
+    namespace: Arc<str>,
     /// Quorum size for exclusive/write operations
     quorum: usize,
 }
@@ -496,6 +496,11 @@ struct LockAcquireQuorumResult {
 impl DistributedLock {
     /// Create new distributed lock
     pub fn new(namespace: String, clients: Vec<Arc<dyn LockClient>>, quorum: usize) -> Self {
+        Self::new_shared(namespace.into(), clients, quorum)
+    }
+
+    /// Create a distributed lock that shares an existing namespace allocation.
+    pub(crate) fn new_shared(namespace: Arc<str>, clients: Vec<Arc<dyn LockClient>>, quorum: usize) -> Self {
         let q = if clients.len() <= 1 {
             1
         } else {